Optical measurement of temperature in tissue culture surfaces under infrared laser light excitation at 800nm using a fluorescent dye

The use of infrared laser light (IRLL) for biomedical applications has gained momentum the potential applications in humans. The use of IRLL presents some limitations due to the dangerousness of these radiations when exceeding some safety thresholds depending on the target tissue. This position paper describes step by step a well-known technical method usually applied for microfluidics but here applied for the first time to measure the temperature and the heat evolution in a cell culture environment under IRLL excitation at 800 nm. The measurement of temperature is based on the property of Rhodamine B (RhB), a fluorescent dye whose fluorescence intensity decreases linearly with temperature increases, illustrated by preliminary microscopic measurements of temperature in cell culture dishes containing RhB solution under the IRLL excitation from 0 mW to 300 mW.